[Overview]
It is a perennial, but because it has weak cold tolerance it is mainly treated as an annual in Japan.
The whole plant is usually fragrant.
Leaves are simple and opposite, with hairs and glandular dots, and have toothed margins.
The flowers are borne in large numbers in verticillasters at the stem tips; they are two-lipped, and the flower colors include pink, purple and white.
The fruit is a schizocarp.
[Cultivation]
Propagate by stem cuttings.
If brought into a sunny room in winter, it can overwinter and be grown as a perennial.
It prefers fertile soil with good sunlight, ventilation, drainage, water retention and aeration.
Direct summer sun weakens it, so in midsummer move it to partial shade to keep it cool.
If the light is too poor, the leaf color and flowering suffer.
Take care not to overwater; from spring to autumn, water thoroughly when the soil surface dries, and keep it on the dry side in winter.
Apply slow-release fertilizer as a base fertilizer, and also place slow-release fertilizer on the soil in spring and autumn.
There are no particular pests or diseases.
